Reflection photoplethysmography of arterial-blood-volume pulses

1977 ◽  
Vol 15 (1) ◽  
pp. 22-31 ◽  
Author(s):  
J. Weinman ◽  
A. Hayat ◽  
G. Raviv
Keyword(s):  
Blood Volume ◽  
Arterial Blood ◽  
Arterial Blood Volume

scholarly journals The VEGF gene polymorphism impacts brain volume and arterial blood volume

2017 ◽  
Author(s):  
Hikaru Takeuchi ◽  
Hiroaki Tomita ◽  
Yasuyuki Taki ◽  
Yoshie Kikuchi ◽  
Chiaki Ono ◽  
...  
Keyword(s):  
Gene Polymorphism ◽  
Blood Volume ◽  
Brain Volume ◽  
Vegf Gene ◽  
Arterial Blood ◽  
Arterial Blood Volume ◽  
Vegf Gene Polymorphism

scholarly journals Pathogenesis and Treatment of Refractory Oedema in Nephrotic Syndrome

EMJ Urology ◽  
2021 ◽  
pp. 107-117
Author(s):  
Priyanka Jethwani ◽  
Namrata Krishnan
Keyword(s):  
Clinical Trials ◽  
Nephrotic Syndrome ◽  
Blood Volume ◽  
Loop Diuretics ◽  
Primary Role ◽  
Sodium Retention ◽  
Oedema Formation ◽  
Arterial Blood ◽  
Filtration Barrier ◽  
Arterial Blood Volume

Oedema is a hallmark feature of nephrotic syndrome (NS) and can cause significant patient morbidity. The pathogenesis of oedema formation is complex and results from abnormalities in sodium retention, inter-play of neurohormonal factors, and changes in capillary filtration barrier. Salt retention is often primary (‘overfill’ theory) because of increased sodium-potassium adenosine triphosphatase activity in the collecting duct cells, increased direct epithelial sodium channel activation (ENaC) by urinary proteases (independent of aldosterone), and an overall increased effective arterial blood volume. However, a subset of patients with NS, especially children, demonstrate decreased effective arterial blood volume (‘underfill’ theory) and secondary sodium retention as the primary mechanism of oedema formation. Increased capillary permeability and vascular inflammation contributes as well. Loop diuretics with or without salt-poor albumin are the mainstay of therapy in adults, although no large clinical trials exist to guide diuretic choice or dosage. Combination diuretic therapy is recommended to achieve multi-site nephron blockade and overcome diuretic resistance, which is a frequent challenge. Use of direct ENaC inhibitors (amiloride) in combination with loop diuretics may be especially beneficial given the primary role of ENaC in sodium retention. Aquaretics such as vasopressin receptor antagonists may have a role in treatment as well. Well-designed clinical trials are essential to guide therapy of refractory oedema in NS. In this review, the authors discuss the pathogenesis of oedema formation in patients with NS and propose a treatment algorithm for management of resistant oedema based on the limited available evidence.

scholarly journals Similarities and Differences in Arterial Responses to Hypercapnia and Visual Stimulation

2010 ◽  
Vol 31 (2) ◽  
pp. 560-571 ◽  
Author(s):  
Yi-Ching Lynn Ho ◽  
Esben Thade Petersen ◽  
Ivan Zimine ◽  
Xavier Golay
Keyword(s):  
Blood Volume ◽  
Transit Time ◽  
Gray Matter ◽  
Visual Stimulation ◽  
Vascular System ◽  
Blood Oxygen Level Dependent ◽  
Blood Oxygen Level ◽  
Functional Studies ◽  
Arterial Blood ◽  
Arterial Blood Volume

Despite the different origins of cerebrovascular activity induced by neurogenic and nonneurogenic conditions, a standard assumption in functional studies is that the consequence on the vascular system will be mechanically similar. Using a recently developed arterial spin labeling method, we examined arterial blood volume, arterial-microvascular transit time, and cerebral blood flow (CBF) in the gray matter and in areas with large arterial vessels under hypercapnia, visual stimulation, and a combination of the two. Spatial heterogeneity in arterial reactivity was observed between conditions. During hypercapnia, large arterial volume changes contributed to CBF increase and further downstream, there were reductions in the gray matter transit time. These changes were not significant during visual stimulation, and during the combined condition they were moderated. These findings suggest distinct vascular mechanisms for large and small arterial segments that may be condition specific. However, the power relationships between gray matter arterial blood volume and CBF in hypercapnia (α = 0.69 ± 0.24) and visual stimulation (α = 0.68 ± 0.20) were similar. Assuming consistent capillary and venous volume responses across these conditions, these results offer support for a consistent total CBV–flow relationship typically assumed in blood oxygen-level dependent calibration techniques.

scholarly journals Correlation between arterial blood volume obtained by arterial spin labelling and cerebral blood volume in intracranial tumours

2011 ◽  
Vol 24 (4) ◽  
pp. 211-223 ◽  
Author(s):  
Danielle van Westen ◽  
Esben T. Petersen ◽  
Ronnie Wirestam ◽  
Roger Siemund ◽  
Karin Markenroth Bloch ◽  
...  
Keyword(s):  
Blood Volume ◽  
Cerebral Blood Volume ◽  
Arterial Spin Labelling ◽  
Intracranial Tumours ◽  
Arterial Blood ◽  
Arterial Blood Volume ◽  
Spin Labelling

Observations on Edema Formation and Resolution in Gleich Syndrome: Essential Role of the Kidneys in Effective Arterial Blood Volume Regulation

2001 ◽  
Vol 21 (2) ◽  
pp. 154-161 ◽  
Author(s):  
Cagatay Oktenli ◽  
Fatih Bulucu ◽  
Murat Gurbuz ◽  
Ergün Bozoglu ◽  
Yusuf Oguz ◽  
...  
Keyword(s):  
Blood Volume ◽  
Volume Regulation ◽  
Essential Role ◽  
Edema Formation ◽  
Arterial Blood ◽  
Arterial Blood Volume

Effects of lung inflation on pulmonary arterial blood volume in intact dogs

1975 ◽  
Vol 38 (4) ◽  
pp. 675-680 ◽  
Author(s):  
A. Wanner ◽  
S. Zarzecki ◽  
M. A. Sackner
Keyword(s):  
Arterial Pressure ◽  
Blood Volume ◽  
Lung Volume ◽  
Pulmonary Arterial Pressure ◽  
Valsalva Maneuver ◽  
Lung Inflation ◽  
Arterial Blood ◽  
Mueller Maneuver ◽  
Pulmonary Arterial ◽  
Arterial Blood Volume

The isolated effects of alterations of lung inflation and transmural pulmonary arterial pressure (pressure difference between intravascular and pleural pressure) on pulmonary arterial blood volume (Vpa) were investigated in anesthetized intact dogs. Using transvenous phrenic nerve stimulation, changes in transmural pulmonary arterial pressure (Ptm) at a fixed transpulmonary pressure (Ptp) were produced by the Mueller maneuver, and increases in Ptp at relatively constant Ptm by a quasi-Valsalva maneuver. Also, both Ptm and Ptp were allowed to change during open airway lung inflation. Vpa was determined during these three maneuvers by multiplying pulmonary blood flow by pulmonary arterial mean transit time obtained by an ether plethysmographic method. During open airway lung inflation, mean (plus or minus SD) Ptp increased by 7.2 (plus or minus 3.7) cmH2O and Ptm by 4.3 (plus or minus 3.4) cmH2O for a mean increase in Vpa by 26.2 (plus or minus 10.7) ml. A pulmonary arterial compliance term (Delta Vpa/Delta Ptm) calculated from the Mueller maneuver was 3.9 ml/cmH2O and an interdependence term (Delta Vpa/Delta Ptp) calculated from the quasi-Valsalva maneuver was 2.5 ml/cmH2O for a 19% increase in lung volume, and 1.2 ml/cmH2O for an increase in lung volume from 19% to 35%. These findings indicate that in normal anesthetized dogs near FRC for a given change in Ptp and Ptm the latter results in a greater increase of Vpa.

scholarly journals Changes in the Arterial Fraction of Human Cerebral Blood Volume during Hypercapnia and Hypocapnia Measured by Positron Emission Tomography

2005 ◽  
Vol 25 (7) ◽  
pp. 852-857 ◽  
Author(s):  
Hiroshi Ito ◽  
Masanobu Ibaraki ◽  
Iwao Kanno ◽  
Hiroshi Fukuda ◽  
Shuichi Miura
Keyword(s):  
Positron Emission Tomography ◽  
Blood Volume ◽  
Cerebral Blood Volume ◽  
Venous Blood ◽  
Capillary Blood ◽  
Emission Tomography ◽  
Arterial Blood ◽  
Positron Emission ◽  
Capillary Blood Volume ◽  
Arterial Blood Volume

Hypercapnia induces cerebral vasodilation and increases cerebral blood volume (CBV), and hypocapnia induces cerebral vasoconstriction and decreases CBV. Cerebral blood volume measured by positron emission tomography (PET) is the sum of three components, that is, arterial, capillary, and venous blood volumes. Changes in arterial blood volume ( Va) and CBV during hypercapnia and hypocapnia were investigated in humans using PET with H215O and 11CO. Arterial blood volume was determined from H215O PET data by means of a two-compartment model that takes Va into account. Baseline CBV and values during hypercapnia and hypocapnia in the cerebral cortex were 0.034 ± 0.003, 0.038 ± 0.003, and 0.031 ± 0.003 mL/mL (mean ± s.d.), respectively. Baseline Va and values during hypercapnia and hypocapnia were 0.015 ± 0.003, 0.025 ± 0.011, and 0.007 ± 0.003 mL/mL, respectively. Cerebral blood volume changed significantly owing to changes in PaCO2, and Va changed significantly in the direction of CBV changes. However, no significant change was observed in venous plus capillary blood volume (= CBV- Va). This indicates that changes in CBV during hypercapnia and hypocapnia are caused by changes in arterial blood volume without changes in venous and capillary blood volume.

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